EntropyThese processes are shown in reverse. The situations shown are so highly improbable that we would not expect to observe them in nature.

Thermodynamics

Endothermic ReactionSolid barium hydroxide octahydrate (Ba(OH)2*8H2O) and ammonium thiocyanate (NH4SCN) are mixed in a beaker, which is then placed on a few drops of water on a small board. The reaction that occurs is highly endothermic.

The Correlation of Binary Acid Strengths with Molecular Properties in First-Year ChemistryTravis D. FridgenThis article replaces contradictory explanations for the strengths of different binary acids in first-year chemistry textbooks with a single explanation that uses a BornHaber cycle involving homolyic bond dissociation energies, electron affinities, and ion solvation enthalpies to rationalize trends in the strengths of all binary acids.Fridgen, Travis D. J. Chem. Educ.2008, 85, 1220.

Acids / Bases |

Atomic Properties / Structure |

Aqueous Solution Chemistry |

Physical Properties |

Thermodynamics

Appreciating OxygenHilton M. WeissPhotosynthetic flora and microfauna utilize light from the sun to convert carbon dioxide and water into carbohydrates and oxygen. While these carbohydrates and their derivative hydrocarbons are generally considered to be fuels, it is the thermodynamically energetic oxygen molecule that traps, stores, and provides almost all of the energy that powers life on earth.Weiss, Hilton M. J. Chem. Educ.2008, 85, 1218.

Bioenergetics |

Metabolism |

Oxidation / Reduction |

Photosynthesis |

Thermodynamics

Undergraduates' Understanding of EntropyArnd H. JungermannSzbilir and Bennett carried out an extensive investigation on undergraduates understanding of entropy. Though I agree in general with their statements that orderdisorder arguments form a misleading entropy concept, I would like to make some comments with regard to a certain part of their online supplement.Jungermann, Arnd H. J. Chem. Educ.2008, 85, 1192.

Disorder (GCMP)David M. WhisnantDisorder: this is a resource in the collection "General Chemistry Multimedia Problems". A spontaneous change is one that has a natural tendency to occur without needing to be driven by an external influence. This problem will explore the influence of entropy, a measure of disorder, on the spontaneity of a few processes. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

Thermodynamics

Two Solids (GCMP)David M. WhisnantTwo Solids: this is a resource in the collection "General Chemistry Multimedia Problems". When two solids barium hydroxide octahydrate, Ba(OH)2. 8H2O and ammonium thiocyanate, NH4SCN are mixed, they react. We will explore the thermodynamics of the reaction. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.